1. Field of the Invention
The present invention relates generally to lighting control systems and, more particularly, to a lighting monitoring system for use with an automated teller machine (ATM) which directly measures source luminance to indirectly determine in the area surrounding the ATM and which effectively alerts customers in the event of a dimly lit and potentially dangerous condition.
2. Description of the Related Art
The typical automated teller machine (ATM) installation includes customer interactive elements such as a keypad and currency door, as well as remote communication elements such as telemetry equipment, which communicates with a central station to notify the station when the machine is out of cash or when the machine encounters mechanical failures. The typical ATM installation also includes shut down mechanisms for closing the cash door and taking the machine out of service.
The growing popularity of ATM use, however, has resulted in an increase in crimes that take place near the ATM. As a result, various governmental bodies have passed laws and regulations which mandate minimum light level requirements in the area surrounding the ATM. The State of California, for example, requires that the level of illumination in the area surrounding the ATM be at least 10 foot-candles when measured anywhere among an arc located at a five (5) foot radius from the ATM and at thirty-six (36) inches above grade.
In view of the fact that dimly lit ATM installations are more susceptible to crime, some of the newer ATM's include a system for notifying the central location when the ambient lighting about the ATM installation falls below a certain minimum threshold or value. Such systems may also disable the ATM if the illumination drops below the prescribed minimum.
The system disclosed in U.S. Pat. No. 5,774,052 is typical of the current light level monitoring systems that use photosensors to directly measure illumination arriving in the area surrounding the ATM. FIG. 4 of the '052 patent, for example, shows an ATM 12 that is illuminated by two lamps 21, 21 and a light sensor assembly 23S that is remotely located relative to the ATM 12 so as to measure the level of illumination in the area surrounding the ATM. Unfortunately, this approach to measuring illumination has several possible drawbacks.
First, because the light sensor assembly 23S must be remotely positioned relative to the ATM 12 in order to "see" the illuminated customer area, the assembly 23S must often be mounted in a position that is not conveniently serviced with wires that supply power or return light measurement signals. Accordingly, it is often necessary to use battery powered light sensor assemblies that use wireless links such as radio frequency (RF) communications, a situation that is obviously undesirable in the context of consumer safety since the batteries will discharge over time and must, therefore, be frequently serviced. The '052 patent, in fact, focuses on an RF system wherein the light sensor assembly 23S only transmits when it determines that the light is below a certain level. It seems, therefore, that the light sensor assembly could fail to communicate a low light level condition due to a malfunction or due to insufficient battery power.
Second, directly measuring the illumination in the customer area in front of the ATM, or elsewhere, without using an incident light meter is undesirable because the measured value is determined by the reflectance of the ATM area, which may change due to the presence of a customer or other environmental conditions. For example, if a customer wearing dark clothing stands before the ATM, the reflected illumination from the light sources will be reduced by the customer's clothing. The measured illumination, therefore, will differ from illumination that would be measured by an incident light meter. The same phenomena may occur when rain covers the illuminated area with a layer of water, which greatly changes the reflection characteristics of dry concrete.
Accordingly, there is a need for a light level monitoring and control system for automated teller machines that does not depend on the reflectance of the illuminated area, but rather directly measures one or more light sources to indirectly determine the area illumination.